PERCROScuola Superiore S. Anna1 “Detailed Workplan for 2005” Pisa – April 11-12, 2005 HAPTEX 2 nd Technical Meeting PERCRO

PERCROScuola Superiore S. Anna2 Role of PERCRO in HAPTEX – Overview WPRole of PERCRO WP1 Contribution to the System Requirements Contribution to the definition of the System Architecture WP2 Support on the Test Activity of the Haptic Renderer WP4 Leader of Workpackage Responsible for the Complete HI Specifications Design and development of the Force Feedback Device Responsible for the Complete HI Integration WP5 Contribution to the VR System Integration WP6 Contribution to Management and Dissemination

PERCROScuola Superiore S. Anna3 Plan of Activities for Main Goals: 1.Definition of the Physical Interaction with Virtual Textiles (WP1) 2.Definition of the SW/Logical interface with the Haptic Renderer (WP1) 3.HW Interface (Mechanical & Electrical) with Tactile Actuators (WP4) 4.Specifications of the Complete Haptic Interface (WP4) 5.Preliminary Design of the Force Feedback Device (WP4)

PERCROScuola Superiore S. Anna4 Goal 1 Definition of the Physical Interaction with Virtual Textiles The fabric hangs in air from a stand. The user draws up his fingers to fabric, pinch and rub it using the thumb and index fingertips and stretch it against the stand. The fabric is wrapped on a soft material (like a pillow). The core of the soft material is fixed in space. The user draws up his hand to the virtual pillow. He can shrink, press, rub interacting with the palmar side of the finger (one or more than one). The fabric is placed on a rigid wall. Its boundaries are rigidly attached on the wall. The user can press his index and thumb fingertips on the fabric and rub and stretch it. How the user will haptically interact with the virtual textile? CASE ACASE BCASE C EXAMPLES OF POSSIBLE INTERACTIONS

PERCROScuola Superiore S. Anna5 Goal 2 Definition of the SW/Logical Interface with the Haptic Renderer Variables to be transmitted Minimum refresh rate Maximum latency Protocol Content: Haptic Renderer Kinesthetic Haptic Interface Tactile Actuators VR Engine ? ? ? ?

PERCROScuola Superiore S. Anna6 Goal 3 HW Interface (Mechanical & Electrical) with Tactile Actuators Weight / Encumbrance of Tactile Actuators Mechanical Attachment with the Force Feedback Device Number and Type of Electrical Wires Allowable Bending Radius of Electrical Wires Content:

PERCROScuola Superiore S. Anna7 Goal 4 Specifications of the Complete Haptic Interface Global Forces on Contact Areas (Force Feedback) Contact Areas Number of Independent Force Components Max Continuous and Peak Force Intensity Force Accuracy, Resolution and Bandwidth Tracked Workspace and Max Speed of Contact Areas Tactile Stimulation (Tactile Feedback) Spatial Resolution Total number of Tactors per Contact Area Force Accuracy, Resolution and Bandwidth per Tactor External Interface With the user (limb supporting the device, wearing requirements etc.) Electrical & SW interface General Constraints Max Allowable Weight Allowable Minimal Distance between Fingers Indicative List of Specifications:

PERCROScuola Superiore S. Anna8 Goal 4 Specifications of the Complete Haptic Interface Contact Areas (where the forces are exerted?) Workspace (which is the extent of movements?) Forces (how many indipendent force components?) Which haptic interaction? Good Fair Not suitable HI configurations defined in the TA

PERCROScuola Superiore S. Anna9 Goal 5 Preliminary Design of the Force Feedback Device Configuration A 2 contact areas 3 independent force components per CA 6 independent actuators 11 contact areas 1 independent force components per CA 12 independent actuators New Device 1 New Device 2 HAPTEX Specs Refurbishment and adaptation of the Existing Device Design from scratch of a new implementation concept Past experience (2002) Past experience (1994) HAPTEX Specs Configuration B PERCRO will develop 2 different HI Device Configurations

PERCROScuola Superiore S. Anna10 Configuration A Pincher The Pincher is composed by two identical micro- manipulators. The bases of the devices are integral with the user’s forearm. If the bases are fixed in space, the user can perform only the flexion/extension and abduction/adduction of the palm and the flexion- extension of the finger’s articulations. Global movements of the forearm require an extra device (like an exoskeleton, or a passive gravity balancer). The dynamic characteristic of the device is excellent (low moving mass). The GRAB is composed by two identical macro-manipulators. The bases of the two manipulators are fixed on the desktop. The user can move his hands and fingers freely in space within the workspace limits of the two devices. The dynamic characteristic of the device is good. PAST EXPERIENCE GRAB

PERCROScuola Superiore S. Anna11 Configuration A REFURBISHMENT OF EXISTING DEVICE Activities to allow the mechanical and electrical integration of the tactile actuators of UNEXE. New Dimensioning and Selection of Actuators Redesign of the Gimbal and of the Links Analsys of the Routing of the Electrical Wire General Goal

PERCROScuola Superiore S. Anna12 Configuration B PAST EXPERIENCE Hand Exos (1994) The Hand Exos is composed by four independent exoskeletons, one for each finger (little excluded). Each finger exoskeleton has 4 DOFs, 3 of which sensorized and actuated and only 1 sensorized. It employs 12 DC iron-less servomotors remotely located on the dorsal side of the palm and in tension tendon unilateral transmissions. The measure of the forces is performed by built-in force sensors based on metallic strain gauges. Drawbacks Tests performed on the device have demonstrated that the unilateral mechanical transmissions are critical for a practical use.

PERCROScuola Superiore S. Anna13 Configuration B DESIGN FROM SCRATCH Activities Analysis of the State of Art Architectural Design Preliminary Design Detailed Design

PERCROScuola Superiore S. Anna14 Configuration B DESIGN FROM SCRATCH Analysis of the State of Art Cyber Grasp (Virtual Tecnologies) 2 coupled force components on the last two phalanxes of all fingers 5 DC Motors remotely located in a Fixed Box Mechanical Transmission with Sheathed Tendons Mass 453g Max continous force 12N Workspace: sphere with radius 1m from actuation system the user feels disturbing forces not correlated to the simulation high friction cable-sheath (stick-slip) low stiffness (long tendons) extra encumbrance of the external fixed box Drawbacks

PERCROScuola Superiore S. Anna15 Analysis of the State of Art (cont) Rutger Master II-ND (Rutger University) L. R. P. Force Feedback Data Glove 1 independent force component for each finger, little excluded 4 pneumatic motors on-board mass 80g max force: 16N min force 0,014N workspace: sphere with radius 2m from air supply system 3 independent force components for each finger, 1 for each phalanx 14 DC motors remotely located in a fixed box sheathed cables mechanical transmission mass of aluminium structure 350g the direction of the exerted force is dependent with the finger posture the device doesn’t allow the complete closure of the hand low stiffness (compressible fluid) high friction (due to the air sealing) the user feels disturbing forces not correlated to the simulation high friction cable-sheath (stick-slip) low stiffness (long tendons) extra encumbrance of the external fixed box Drawbacks

PERCROScuola Superiore S. Anna16 Configuration B DESIGN FROM SCRATCH Architectural Design Components Lay-Out Reference Configuration Kinematic Isomorphic with the Physiological one Iron-less DC Servomotor Actuators located on the dorsal side of the palm Bilateral Long Transmissions with in Tension Tendons Strain Gauges for the measure of the Exerted Forces Class A (not PWM) Current Drivers All the mechanical components are located on the dorsal side of the hand. Motors Position Sensors Force Sensors Linkage

PERCROScuola Superiore S. Anna17 Configuration B DESIGN FROM SCRATCH Preliminary Design Identification / Selection of the Remote Center of Rotation Mechanism (RCRM) Identification of the Scheme for the Bilateral Tendon Transmission Preliminary Performance Evaluation ( Stiffness, Inertia, Torque Requirements,... ) Selection of the DC Torque Motor and of the Position Sensors Preliminary Dimensioning of the Force Sensor Preliminary 3D Modeling of the Mechanical Assembly Activities

PERCROScuola Superiore S. Anna18 Configuration B DESIGN FROM SCRATCH Detailed Design Weight and Encumbrance Reduction High Density Packaging of Mechanical & Electrical Components: Actuators Sensors (Position, Force) Links Wires Tendon Transmissions Conditioning & Communication Electronics ( embedded in the mechanics ) Routing & Wiring of the Electrical Cables Reliability of the Complete Device Technical Challenges

PERCROScuola Superiore S. Anna19Deadlines GoalTitleDeadline 1 Definition of the Physical Interaction with Virtual Textiles (WP1) June Definition of the SW/Logical Interface with the Haptic Renderer (WP1) June HW Interface (Mechanicl & Electrical) with Tactile Actuators (WP4) Oct Specifications of the Complete Haptic Interface (WP4) Nov Preliminary Design of the Force Feedback Device (WP4) Dec 2005